[PATCH] spin_lock_irq debugging

[Duncan Sands]

Of course the real problem is the corresponding spin_unlock_irq
enabling local irqs when they should have been left disabled, but
this is easier to check for.  Your logs will fill up.

diff -Nru a/include/linux/spinlock.h b/include/linux/spinlock.h
--- a/include/linux/spinlock.h	Wed May 21 22:04:29 2003
+++ b/include/linux/spinlock.h	Wed May 21 22:04:29 2003
@@ -261,6 +261,10 @@
 
 #define spin_lock_irq(lock) \
 do { \
+	if (unlikely(irqs_disabled())) { \
+		printk(KERN_ERR "bad: spin_lock_irq with irqs disabled!\n"); \
+		dump_stack(); \
+	} \
 	local_irq_disable(); \
 	preempt_disable(); \
 	_raw_spin_lock(lock); \